Vaccinia

This article is about the virus related to smallpox vaccines. For the plant genus, see Vaccinium.
Not to be confused with vaccine.
Orthopoxvirus vaccinia
A TEM micrograp of "Vaccinia virus" virions
A TEM micrograph of Vaccinia virus virions
Virus classification Edit this classification
(unranked): Virus
Realm: Varidnaviria
Kingdom: Bamfordvirae
Phylum: Nucleocytoviricota
Class: Pokkesviricetes
Order: Chitovirales
Family: Poxviridae
Genus: Orthopoxvirus
Species:
Orthopoxvirus vaccinia
Member viruses[1]
Vaccinia
SpecialtyVirology
TypesProgressive vaccinia

The vaccinia virus (VACV or VV)[a] is a large, complex, enveloped virus belonging to the poxvirus family.[3] It has a linear, double-stranded DNA genome approximately 190 kbp in length, which encodes approximately 250 genes. The dimensions of the virion are roughly 360 × 270 × 250 nm, with a mass of approximately 5–10 fg.[4] The vaccinia virus is the source of the modern smallpox vaccine, which the World Health Organization (WHO) used to eradicate smallpox in a global vaccination campaign in 1958–1977. Although smallpox no longer exists in the wild, vaccinia virus is still studied widely by scientists as a tool for gene therapy and genetic engineering.

Smallpox had been an endemic human disease that had a 30% fatality rate. In 1796, the British doctor Edward Jenner proved that an infection with the relatively mild cowpox virus would also confer immunity to the deadly smallpox. Jenner referred to cowpox as variolae vaccinae (smallpox of the cow). However, the origins of the smallpox vaccine became murky over time,[5] especially after Louis Pasteur developed laboratory techniques for creating vaccines in the 19th century. Allan Watt Downie demonstrated in 1939 that the modern smallpox vaccine was serologically distinct from cowpox,[6] and vaccinia was subsequently recognized as a separate viral species. Whole-genome sequencing has revealed that vaccinia is most closely related to horsepox, and the cowpox strains found in Great Britain are the least closely related to vaccinia.[7]

  1. ^ "ICTV 9th Report (2011) Poxviridae". International Committee on Taxonomy of Viruses (ICTV). Archived from the original on 8 August 2022. Retrieved 17 December 2018.
  2. ^ "Taxon Details | ICTV". ictv.global. Retrieved 2024-08-30.
  3. ^ Ryan KJ, Ray CG, eds. (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. ISBN 978-0-8385-8529-0.
  4. ^ Johnson, L.; Gupta, A. K.; Ghafoor, A.; Akin, D.; Bashir, R. (2006). "Characterization of vaccinia virus particles using microscale silicon cantilever resonators and atomic force microscopy". Sensors and Actuators B Chemical. 115 (1): 189–197. doi:10.1016/j.snb.2005.08.047.
  5. ^ Baxby, Derrick (1981). Jenner's Smallpox Vaccine: The Riddle of Vaccinia Virus and Its Origin. Heinemann Educational Books. ISBN 978-0-435-54057-9.
  6. ^ Cite error: The named reference downie1939 was invoked but never defined (see the help page).
  7. ^ Carroll, Darin S.; Emerson, Ginny L.; Li, Yu; Sammons, Scott; Olson, Victoria; Frace, Michael; Nakazawa, Yoshinori; Czerny, Claus Peter; Tryland, Morten; Kolodziejek, Jolanta; Nowotny, Norbert; Olsen-Rasmussen, Melissa; Khristova, Marina; Govil, Dhwani; Karem, Kevin; Damon, Inger K.; Meyer, Hermann (8 August 2011). "Chasing Jenner's Vaccine: Revisiting Cowpox Virus Classification". PLOS ONE. 6 (8): e23086. Bibcode:2011PLoSO...623086C. doi:10.1371/journal.pone.0023086. ISSN 1932-6203. PMC 3152555. PMID 21858000.


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